The statements in this section merely provide background information related to the present disclosure and may not constitute prior art.
Electrically-conductive elastomer seals and gasket products sometimes are configured to provide electromagnetic interference (EMI) shielding and provide environmental sealing. For example, a seal or gasket may be required to keep out contaminates, such as dust and moisture. Other times, a seal or gasket may be required to hold back a pressure differential, as in the case of a submersible camera.
Gaskets and seals have also been developed for use in gaps and around doors to provide a degree of EMI shielding while permitting operation of enclosure doors and access panels and fitting of connectors. To shield EMI effectively, the gasket should be capable of absorbing or reflecting EMI as well as establishing a continuous electrically conductive path across the gap in which the gasket is disposed. These gaskets can also be used for maintaining electrical continuity across a structure and for excluding from the interior of the device such contaminates as moisture and dust. Once installed, the gaskets essentially close or seal any interface gaps and establish a continuous electrically-conductive path thereacross by conforming under an applied pressure to irregularities between the surfaces. Accordingly, gaskets and seals intended for EMI shielding applications are specified to be of a construction that not only provides electrical surface conductivity even while under compression, but which also has a resiliency allowing the seals to conform to the size of the gap.
As used herein, the term “EMI” should be considered to generally include and refer to EMI emissions and RFI emissions, and the term “electromagnetic” should be considered to generally include and refer to electromagnetic and radio frequency from external sources and internal sources. Accordingly, the term shielding (as used herein) generally includes and refers to EMI shielding and RFI shielding, for example, to prevent (or at least reduce) ingress and egress of EMI and RFI relative to a housing or other enclosure in which electronic equipment is disposed.